#ifndef __RenderTarget_H__
#define __RenderTarget_H__


#include "U2PreRequest.h"
#include "U2MemoryAllocatorConfig.h"
#include "U2StringUtil.h"
#include "U2TextureManager.h"
#include "U2Timer.h"
//#include "OgreViewport.h"


/* Define the number of priority groups for the render system's render targets. */
#ifndef U2_NUM_RENDERTARGET_GROUPS
	#define U2_NUM_RENDERTARGET_GROUPS  10
	#define U2_DEFAULT_RT_GROUP         4
	#define U2_REND_TO_TEX_RT_GROUP     2
#endif


U2EG_NAMESPACE_BEGIN


class RenderTargetListener;
class U2DepthBuffer;
class U2Camera;
class U2Viewport;


/** A 'canvas' which can receive the results of a rendering
    operation.
@remarks
    This abstract class defines a common root to all targets of rendering operations. A
    render target could be a window on a screen, or another
    offscreen surface like a texture or bump map etc.
@author
    Steven Streeting
@version
    1.0
 */
class _U2Share U2RenderTarget : public RenderSysAlloc
{
public:
    enum StatFlags
    {
        SF_NONE           = 0,
        SF_FPS            = 1,
        SF_AVG_FPS        = 2,
        SF_BEST_FPS       = 4,
        SF_WORST_FPS      = 8,
        SF_TRIANGLE_COUNT = 16,
        SF_ALL            = 0xFFFF
    };

    struct FrameStats
    {
        float lastFPS;
        float avgFPS;
        float bestFPS;
        float worstFPS;
        unsigned long bestFrameTime;
        unsigned long worstFrameTime;
        size_t triangleCount;
        size_t batchCount;
    };

	enum FrameBuffer
	{
		FB_FRONT,
		FB_BACK,
		FB_AUTO
	};

    U2RenderTarget();
    virtual ~U2RenderTarget();

    /// Retrieve target's name.
    virtual const U2String& getName(void) const;

    /// Retrieve information about the render target.
    virtual void getMetrics(unsigned int& width, unsigned int& height, unsigned int& colourDepth);

    virtual unsigned int getWidth(void) const;
    virtual unsigned int getHeight(void) const;
    virtual unsigned int getColourDepth(void) const;

	/** Sets the pool ID this RenderTarget should query from. Default value is POOL_DEFAULT.
	    Set to POOL_NO_DEPTH to avoid using a DepthBuffer (or manually controlling it) @see DepthBuffer
	@remarks
	    Changing the pool Id will cause the current depth buffer to be detached unless the old
	    id and the new one are the same
	*/
	void setDepthBufferPool( u2uint16 poolId );

	/// Returns the pool ID this RenderTarget should query from. @see DepthBuffer
	u2uint16 getDepthBufferPool() const;

	U2DepthBuffer* getDepthBuffer() const;

	/// Returns false if couldn't attach
	virtual bool attachDepthBuffer( U2DepthBuffer *depthBuffer );

	virtual void detachDepthBuffer();

	/** Detaches DepthBuffer without notifying it from the detach.
		Useful when called from the DepthBuffer while it iterates through attached
		RenderTargets (@see DepthBuffer::_setPoolId())
	*/
	virtual void _detachDepthBuffer();

    /** Tells the target to update it's contents.
    @remarks
        If OGRE is not running in an automatic rendering loop
        (started using Root::startRendering),
        the user of the library is responsible for asking each render
        target to refresh. This is the method used to do this. It automatically
        re-renders the contents of the target using whatever cameras have been
        pointed at it (using U2Camera::setRenderTarget).
    @par
        This allows OGRE to be used in multi-windowed utilities
        and for contents to be refreshed only when required, rather than
        constantly as with the automatic rendering loop.
	@param swapBuffers For targets that support double-buffering, if set 
		to true, the target will immediately
		swap it's buffers after update. Otherwise, the buffers are
		not swapped, and you have to call swapBuffers yourself sometime
		later. You might want to do this on some rendersystems which 
		pause for queued rendering commands to complete before accepting
		swap buffers calls - so you could do other CPU tasks whilst the 
		queued commands complete. Or, you might do this if you want custom
		control over your windows, such as for externally created windows.
    */
    virtual void update(bool swapBuffers = true);
    /** Swaps the frame buffers to display the next frame.
    @remarks
        For targets that are double-buffered so that no
        'in-progress' versions of the scene are displayed
        during rendering. Once rendering has completed (to
        an off-screen version of the window) the buffers
        are swapped to display the new frame.

    @param
        waitForVSync If true, the system waits for the
        next vertical blank period (when the CRT beam turns off
        as it travels from bottom-right to top-left at the
        end of the pass) before flipping. If false, flipping
        occurs no matter what the beam position. Waiting for
        a vertical blank can be slower (and limits the
        framerate to the monitor refresh rate) but results
        in a steadier image with no 'tearing' (a flicker
        resulting from flipping buffers when the beam is
        in the progress of drawing the last frame).
    */
    virtual void swapBuffers(bool waitForVSync = true)
    { (void)waitForVSync; }

    /** Adds a viewport to the rendering target.
    @remarks
        A viewport is the rectangle into which rendering output is sent. This method adds
        a viewport to the render target, rendering from the supplied camera. The
        rest of the parameters are only required if you wish to add more than one viewport
        to a single rendering target. Note that size information passed to this method is
        passed as a parametric, i.e. it is relative rather than absolute. This is to allow
        viewports to automatically resize along with the target.
    @param
        cam The camera from which the viewport contents will be rendered (mandatory)
    @param
        ZOrder The relative order of the viewport with others on the target (allows overlapping
        viewports i.e. picture-in-picture). Higher ZOrders are on top of lower ones. The actual number
        is irrelevant, only the relative ZOrder matters (you can leave gaps in the numbering)
    @param
        left The relative position of the left of the viewport on the target, as a value between 0 and 1.
    @param
        top The relative position of the top of the viewport on the target, as a value between 0 and 1.
    @param
        width The relative width of the viewport on the target, as a value between 0 and 1.
    @param
        height The relative height of the viewport on the target, as a value between 0 and 1.
    */
    virtual U2Viewport* addViewport(U2Camera* cam, int ZOrder = 0, float left = 0.0f, float top = 0.0f ,
        float width = 1.0f, float height = 1.0f);

    /** Returns the number of viewports attached to this target.*/
    virtual unsigned short getNumViewports(void) const;

    /** Retrieves a pointer to the viewport with the given index. */
    virtual U2Viewport* getViewport(unsigned short index);

	/** Retrieves a pointer to the viewport with the given zorder. 
		@remarks throws if not found.
	*/
    virtual U2Viewport* getViewportByZOrder(int ZOrder);

	/** Returns true if and only if a viewport exists at the given ZOrder. */
	virtual bool hasViewportWithZOrder(int ZOrder);

    /** Removes a viewport at a given ZOrder.
    */
    virtual void removeViewport(int ZOrder);

    /** Removes all viewports on this target.
    */
    virtual void removeAllViewports(void);

    /** Retieves details of current rendering performance.
    @remarks
        If the user application wishes to do it's own performance
        display, or use performance for some other means, this
        method allows it to retrieve the statistics.
    @param
        lastFPS Pointer to a float to receive the number of frames per second (FPS)
        based on the last frame rendered.
    @param
        avgFPS Pointer to a float to receive the FPS rating based on an average of all
        the frames rendered since rendering began (the call to
        Root::startRendering).
    @param
        bestFPS Pointer to a float to receive the best FPS rating that has been achieved
        since rendering began.
    @param
        worstFPS Pointer to a float to receive the worst FPS rating seen so far.
    */
    virtual void getStatistics(float& lastFPS, float& avgFPS,
        float& bestFPS, float& worstFPS) const;  // Access to stats

    virtual const FrameStats& getStatistics(void) const;

    /** Individual stats access - gets the number of frames per second (FPS) based on the last frame rendered.
    */
    virtual float getLastFPS() const;

    /** Individual stats access - gets the average frames per second (FPS) since call to Root::startRendering.
    */
    virtual float getAverageFPS() const;

    /** Individual stats access - gets the best frames per second (FPS) since call to Root::startRendering.
    */
    virtual float getBestFPS() const;

    /** Individual stats access - gets the worst frames per second (FPS) since call to Root::startRendering.
    */
    virtual float getWorstFPS() const;

    /** Individual stats access - gets the best frame time
    */
    virtual float getBestFrameTime() const;

    /** Individual stats access - gets the worst frame time
    */
    virtual float getWorstFrameTime() const;

    /** Resets saved frame-rate statistices.
    */
    virtual void resetStatistics(void);

    /** Gets a custom (maybe platform-specific) attribute.
        @remarks
            This is a nasty way of satisfying any API's need to see platform-specific details.
            It horrid, but D3D needs this kind of info. At least it's abstracted.
        @param
            name The name of the attribute.
        @param
            pData Pointer to memory of the right kind of structure to receive the info.
    */
    virtual void getCustomAttribute(const U2String& name, void* pData);

    /** Add a listener to this RenderTarget which will be called back before & after rendering.
    @remarks
        If you want notifications before and after a target is updated by the system, use
        this method to register your own custom RenderTargetListener class. This is useful
        for potentially adding your own manual rendering commands before and after the
        'normal' system rendering.
    @par NB this should not be used for frame-based scene updates, use Root::addFrameListener for that.
    */
    virtual void addListener(RenderTargetListener* listener);
    /** Removes a RenderTargetListener previously registered using addListener. */
    virtual void removeListener(RenderTargetListener* listener);
    /** Removes all listeners from this instance. */
    virtual void removeAllListeners(void);

	/** Sets the priority of this render target in relation to the others. 
    @remarks
        This can be used in order to schedule render target updates. Lower
        priorities will be rendered first. Note that the priority must be set
        at the time the render target is attached to the render system, changes
        afterwards will not affect the ordering.
    */
    virtual void setPriority( u2uchar priority ) { mPriority = priority; }
    /** Gets the priority of a render target. */
	virtual u2uchar getPriority() const { return mPriority; }

    /** Used to retrieve or set the active state of the render target.
    */
    virtual bool isActive() const;

    /** Used to set the active state of the render target.
    */
    virtual void setActive( bool state );

    /** Sets whether this target should be automatically updated if Ogre's rendering
        loop or Root::_updateAllRenderTargets is being used.
    @remarks
        By default, if you use Ogre's own rendering loop (Root::startRendering)
        or call Root::_updateAllRenderTargets, all render targets are updated 
        automatically. This method allows you to control that behaviour, if 
        for example you have a render target which you only want to update periodically.
    @param autoupdate If true, the render target is updated during the automatic render
        loop or when Root::_updateAllRenderTargets is called. If false, the 
        target is only updated when its update() method is called explicitly.
    */
    virtual void setAutoUpdated(bool autoupdate);
    /** Gets whether this target is automatically updated if Ogre's rendering
        loop or Root::_updateAllRenderTargets is being used.
    */
    virtual bool isAutoUpdated(void) const;

	/** Copies the current contents of the render target to a pixelbox. 
	@remarks See suggestPixelFormat for a tip as to the best pixel format to
		extract into, although you can use whatever format you like and the 
		results will be converted.
	*/
	virtual void copyContentsToMemory(const U2PixelBox &dst, FrameBuffer buffer = FB_AUTO) = 0;

	/** Suggests a pixel format to use for extracting the data in this target, 
		when calling copyContentsToMemory.
	*/
	virtual PixelFormat suggestPixelFormat() const { return PF_BYTE_RGBA; }
	
    /** Writes the current contents of the render target to the named file. */
    void writeContentsToFile(const U2String& filename);

	/** Writes the current contents of the render target to the (PREFIX)(time-stamp)(SUFFIX) file.
		@returns the name of the file used.*/
	virtual U2String writeContentsToTimestampedFile(const U2String& filenamePrefix, const U2String& filenameSuffix);

	virtual bool requiresTextureFlipping() const = 0;

	/** Gets the number of triangles rendered in the last update() call. */
	virtual size_t getTriangleCount(void) const;
    /** Gets the number of batches rendered in the last update() call. */
	virtual size_t getBatchCount(void) const;
    /** Utility method to notify a render target that a camera has been removed,
    incase it was referring to it as a viewer.
    */
    virtual void _notifyCameraRemoved(const U2Camera* cam);

    /** Indicates whether this target is the primary window. The
        primary window is special in that it is destroyed when
        ogre is shut down, and cannot be destroyed directly.
        This is the case because it holds the context for vertex,
        index buffers and textures.
    */
    virtual bool isPrimary(void) const;

	/** Indicates whether on rendering, linear colour space is converted to 
		sRGB gamma colour space. This is the exact opposite conversion of
		what is indicated by Texture::isHardwareGammaEnabled, and can only
		be enabled on creation of the render target. For render windows, it's
		enabled through the 'gamma' creation misc parameter. For textures, 
		it is enabled through the hwGamma parameter to the create call.
	*/
	virtual bool isHardwareGammaEnabled() const { return mHwGamma; }

	/** Indicates whether multisampling is performed on rendering and at what level.
	*/
	virtual u2uint getFSAA() const { return mFSAA; }

	/** Gets the FSAA hint (@see Root::createRenderWindow)
	*/
	virtual const U2String& getFSAAHint() const { return mFSAAHint; }

    /** RenderSystem specific interface for a RenderTarget;
        this should be subclassed by RenderSystems.
    */
    class Impl
    {
    protected:
        ~Impl() { }
    };

    /** Get rendersystem specific interface for this RenderTarget.
        This is used by the RenderSystem to (un)bind this target, 
        and to get specific information like surfaces
        and framebuffer objects.
    */
    virtual Impl *_getImpl();

	/** Method for manual management of rendering : fires 'preRenderTargetUpdate'
		and initialises statistics etc.
	@remarks 
	<ul>
	<li>_beginUpdate resets statistics and fires 'preRenderTargetUpdate'.</li>
	<li>_updateViewport renders the given viewport (even if it is not autoupdated),
	fires preViewportUpdate and postViewportUpdate and manages statistics.</li>
	<li>_updateAutoUpdatedViewports renders only viewports that are auto updated,
	fires preViewportUpdate and postViewportUpdate and manages statistics.</li>
	<li>_endUpdate() ends statistics calculation and fires postRenderTargetUpdate.</li>
	</ul>
	you can use it like this for example :
	<pre>
		renderTarget->_beginUpdate();
		renderTarget->_updateViewport(1); // which is not auto updated
		renderTarget->_updateViewport(2); // which is not auto updated
		renderTarget->_updateAutoUpdatedViewports();
		renderTarget->_endUpdate();
		renderTarget->swapBuffers(true);
	</pre>
		Please note that in that case, the zorder may not work as you expect,
		since you are responsible for calling _updateViewport in the correct order.
    */
	virtual void _beginUpdate();

	/** Method for manual management of rendering - renders the given 
	    viewport (even if it is not autoupdated)
	@remarks
	    This also fires preViewportUpdate and postViewportUpdate, and manages statistics.
	    You should call it between _beginUpdate() and _endUpdate().
	@see _beginUpdate for more details.
	@param zorder The zorder of the viewport to update.
	@param updateStatistics Whether you want to update statistics or not.
	*/
	virtual void _updateViewport(int zorder, bool updateStatistics = true);

	/** Method for manual management of rendering - renders the given viewport (even if it is not autoupdated)
	@remarks
	    This also fires preViewportUpdate and postViewportUpdate, and manages statistics
	    if needed. You should call it between _beginUpdate() and _endUpdate().
	@see _beginUpdate for more details.
	@param viewport The viewport you want to update, it must be bound to the rendertarget.
	@param updateStatistics Whether you want to update statistics or not.
	*/
	virtual void _updateViewport(U2Viewport* viewport, bool updateStatistics = true);

	/** Method for manual management of rendering - renders only viewports that are auto updated
	@remarks
	    This also fires preViewportUpdate and postViewportUpdate, and manages statistics.
	    You should call it between _beginUpdate() and _endUpdate().
	    See _beginUpdate for more details.
	@param updateStatistics Whether you want to update statistics or not.
	@see _beginUpdate()
	*/
	virtual void _updateAutoUpdatedViewports(bool updateStatistics = true);
	
	/** Method for manual management of rendering - finishes statistics calculation 
		and fires 'postRenderTargetUpdate'.
	@remarks
	    You should call it after a _beginUpdate
	@see _beginUpdate for more details.
	*/
	virtual void _endUpdate();

protected:
    /// The name of this target.
    U2String        mName;
	/// The priority of the render target.
	u2uchar         mPriority;

    unsigned int    mWidth;
    unsigned int    mHeight;
    unsigned int    mColourDepth;
	u2uint16		mDepthBufferPoolId;
    U2DepthBuffer*    mDepthBuffer;

    // Stats
	FrameStats      mStats;
    
    U2Timer*        mTimer;
    unsigned long   mLastSecond;
    unsigned long   mLastTime;
    size_t          mFrameCount;

    bool            mActive;
    bool            mAutoUpdate;
	// Hardware sRGB gamma conversion done on write?
	bool            mHwGamma;
	// FSAA performed?
	u2uint          mFSAA;
	U2String        mFSAAHint;

    void updateStats(void);

    typedef std::map<int, U2Viewport*>          ViewportList;
    /// List of viewports, map on Z-order
    ViewportList                mViewportList;

    typedef std::vector<RenderTargetListener*>  RenderTargetListenerList;
    RenderTargetListenerList    mListeners;


    /// internal method for firing events
    virtual void firePreUpdate(void);
    /// internal method for firing events
    virtual void firePostUpdate(void);
    /// internal method for firing events
    virtual void fireViewportPreUpdate(U2Viewport* vp);
    /// internal method for firing events
    virtual void fireViewportPostUpdate(U2Viewport* vp);
	/// internal method for firing events
	virtual void fireViewportAdded(U2Viewport* vp);
	/// internal method for firing events
	virtual void fireViewportRemoved(U2Viewport* vp);
	
	/// Internal implementation of update()
	virtual void updateImpl();
};


U2EG_NAMESPACE_END


#endif
